PB1752: SAMATYA-PREDICTING SCORE IN ACUTE LYMPHOBLASTIC LEUKEMIA (ALL): COMBINING CLINICAL FEATURES WITH FLOW CYTOMETRY
Authors: Tahir Alper Cinli, Istemi Serin, Derya Sonmez, Bagnu Orhan, Huriye Serin, Hasan Goze, Osman Yokus
Journal: HemaSphere (2023)

Topic: 2. Acute lymphoblastic leukemia - Clinical Background: Acute lymphoblastic leukemia (ALL) is a disease characterized by the abnormal proliferation of immature lymphoid cells in the bone marrow, peripheral blood, and other organs. Flow cytometric features appear to play a role in addition to laboratory, clinical and genetic factors, which have been defined in the prognosis prediction of hematological malignancies. CD34 expression was found to be associated with poor prognosis in the B-ALL patients and also, CD5, CD7, CD117 and >90% CD45 positivity were found to be negative prognostic indicators among B-ALL patients. Combining well-studied clinical and laboratory risk factors with flow cytometric features is considered a different approach. Aims: In our study, we aimed to develop a scoring system that can be used in the prediction of response to induction and survival by combining previously defined clinical factors and flow cytometric features in B-ALL patients. Methods: Patients who were diagnosed and followed up in Istanbul Training and Research Hospital, Hematology Clinic, and received induction between January 2010 and January 2022 were included in our study. As per the preferred induction regimen in our clinic, Hyper-CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone, alternating with high-dose methotrexate and cytarabine) was utilized. Risk scores were determined by considering the risk classification system according to the characteristics of the patients at the time of diagnosis. The baseline characteristics and the scores they had according to the risk scoring system were recorded and analyzes were performed in terms of both response to induction and survival. Risk scoring system parameters are shown in Table 1. Age (<35 = 0, ≥55 = 1, ≥70 =2), initial leukocyte count (<30000 = 0, ≥30000 =1), subtype (Pro B = 1 and Pre B = 1), presence of extramedullary disease ((-) = 0, (+) =1), presence of tumor lysis during induction therapy ((-)= 0, (+) =1), risk stratification by genetics [2, 12] (good = 0, poor = 1), time to complete remission (<4 weeks = 0, ≥4 weeks = 1) and flow cytometry findings (CD5, CD7, CD117, CD45 >90% Positivity = 1) were recorded and the total score was calculated. Results: In the analysis performed to examine the effect of the calculated risk score of the patients on survival, no statistically significant results were obtained (p>0.05). In the statistical analysis performed to examine the effect on the response to induction, it was observed that the risk score (3.35) was higher in patients who were non-complete responders (p=0.019). According to the ROC analysis, the calculated risk score was not a statistically significant factor in the prediction of survival (p>0.05), while it was found to be a significant factor for the response to induction (p<0.05). The cut-off value for the response to induction was determined as 2.5, based on this the sensitivity was calculated as 65.2% and the specificity as 63.3%. In the statistical analysis based on the cut-off value of 2.5, a significant difference was revealed in terms of survival. The median overall survival (OS) of patients with a risk score of ≥ 2.5 was found to be significantly shorter compared to those with a risk score of <2.5 (for <2.5 17 months, range:1-162; for ≥ 2.5 10 months, range: 1-84; p=0.035). While there was no significant difference between the survival curves for the cut-off value of 2.5 in patients with a non-complete induction response, a significant difference was observed in patients with a mortal course, and OS was significantly shorter in patients with a risk score of ≥2.5 compared to those with a risk score of <2.5. Summary/Conclusion: In conclusion, we aimed to develop a new prognostic scoring system in B-ALL patients in our study. It was revealed that the risk score was higher in the non-responder patient subgroup, the sensitivity for the cut-off value of 2.5 for the response to induction was 65.2%, and the specificity was 63.3%; the OS was found to be shorter in patients with a high-risk score. Table 1. Risk classification of acute B-cell lymphoblastic leukemiaFigure 1. ROC analysis of risk score: Response to inductionFigure 2. Survival analysis of patients: Comparison of patients with a risk score of <2.5 and ≥2.5Keywords: Survival, Prognosis, Flow cytometry, Acute lymphoblastic leukemia